The present invention relates to a movement giver (or actuator) according to the generic term of the independent claim.
Movement givers per se are known. In computer technology, movement givers are used as computer mice, trackballs and the like for the control of the computer cursor. In a conventional computer mouse there is present a ball, turnably borne and partially overhanging a housing surface, which rotates when the housing surface of the mouse is moved over a surface. The rotation of the ball then is measured on two axes.
Besides the mechanical scanning by accompanying rollers, there was proposed for this a large number of arrangements for the detection of movement. A first example is described in EP 0 729 112, which discloses a ball with conductive surfaces insulated from one another, the movement of which is read with capacitor plates integrated into the bearing.
U.S. Pat. No. 5,831,553 discloses an arrangement with a non-magnetic ball into which soft-magnetic particles are admitted. By means of a permanent magnet a magnetic field is generated around the ball from the outside. Between permanent magnet and ball then a magnetic field sensor is arranged. The magnetic field lines run there on the ball surface in dependence on the particle orientation. With a sensor between permanent magnet and ball, changes of the magnetic field are detected, and therewith ball rotations.
In WO 98/36346 it has been proposed magnetically to mark a magnetizable ball locally with a writing head, in order to detect the markings position with reading heads after rotation, and then to erase them (markings) with an erasing head.
Further, from GB 2 272 763 it is known to illuminate an unstructured ball with a laser, and to detect the laser speckles pattern that changes under the ball movement, in order from their change in position to obtain information about the movement direction and the speed of the ball. The evaluation algorithms for determining the movement direction and speed, however, are complicated.
It has also already been proposed, to detect the reflection of a surface with reflection points for the detection of movement, compare WO 94/22971.
It has been proposed, furthermore, to use a structured ball in a computer mouse, with which the position of the structures can be scanned optically, magnetically, capacitively or galvanically, compare EP 0 416 870.
In the state of the art there are problems to the effect that the arrangements used, insofar as technically realizable, are not economical, in which context especially the computing load of the computer through the evaluating process is expensive because thereby higher computing performances are required.
The problem of the present invention lies in making available new information for the industrial application.
The solution of this problem is claimed independently. Preferred forms of execution are found in the subclaims.
There is proposed, therefore, first of all a movement giver especially for control of a computer cursor, with a movable body and a movement sensor for the detection of a body movement, in which it is further provided that the movable body has an after-glowing surface and the movement sensor has a light source for the generation of an after-glowing light spot on the movable body, and a position-sensitive photo-detector, in order to make it possible to track the movement of the after-glowing spot (Fleckes) on the rotary body surface.
A reversal of the principle is likewise possible, so that a light source is moved relatively to a fixed, after-glowing body and the tracer trajectory is tracked on this.
A first essential aspect of the invention lies therefore in that an arrangement is chosen in which neither a complicated structuring of a ball or of another movable object, nor the erasing of a marking, or even a complicated evaluating unit is required, but a simple fading-out (Ausklingen) of a marking signal is used. For this an after-glowing surface is used, while on this a light spot of predetermined location is generated, and its position is detected in the rotary body movement. There is applied, therefore, a quasi self-erasing marking that, insofar as possible, is tracked up to its self-extinction. While the invention is useful especially for spherical movement bodies, its use is also possible with flat geometries.
Although it is possible, for example, to construct the underside of a joystick or the like with an after-glowing surface, as a rotary body which, moreover, must allow a rotation in one direction only, typically the rotary body will have a spherical shape. Another preferred use is as angle-givers, with which an axial position is to be detected.
It is especially advantageous if the rotary body has a small diameter. Diameters of under 4 mm are preferred, especially preferred are those of not more than 2 mm. This makes it possible, with conventional movement course such as the typical shifting of a mouse on a surface, fort the after-glowing to be so far distant from the illumination point that an adequately high resolution is achieved. If the ball has a radius of even only about 0.5 mm, a very compact ballpoint pen-like device can be constructed, in which the ball is rolled off over a surface in the manner of a stylus. The ball size makes it possible, there, to use a movement-giver in stylus form, with a manual operation usual for typical writing instruments. This is especially advantageous when a data detection is provided such that, from the movement trajectory of especially a stylus-form mouse, a writing stroke is identified. This inscription can be used directly in order to make possible the input of whole written texts with a device which can be moved like a conventional writing instrument.
In a preferred example of execution the movement giver will represent a computer mouse, a trackball or a mouse stylus (Mausstift), i.e. a device in stylus form with a frontally arranged rotary body, in which keys or the like can be arranged on the grip body itself, in order to signal a mouse click. In an alternative and/or supplementary manner, a pressing of the mouse stylus on its tip can be used for the keying. It is obvious that two rotation-givers can be provided on the opposite ends of the mouse stylus, say, in order to perform a writing and erasing function, without its being necessary for a corresponding menu point to be called upon in a computer program.
It is preferred if the after-glowing on the surface dies out in at the most 60 milliseconds, preferably in less than 20 milliseconds to an intensity of 1/e of the initial intensity on illumination. The maximum time of 60 ms is yielded as advantageous there from typical manual-movement runs when working with the device according to the invention. Such a short dying-out time ensures that the rotary body also, and precisely with reverse movement, does not have any memory effect, but can be marked again after a certain movement.
It is further preferred if the after-glowing surface falls to a value of 1/e in at the shortest 1 millisecond, but preferably in at least 5 milliseconds. Afterglow times lying below this are so brief that the marked (rotary) body at conventional speeds of movement will possibly not be far enough removed from the illumination point to make it possible to measure the movement.
It is possible to make the after-glowing surface of glass that is doped with a rare earth compound, in which case, for example, erbium-doped glass is to be used. An alternative lies in using zinc sulfide, especially activated zinc sulfide, for the after-glowing surface. It is obvious that it is possible, instead of an only superficially coated (rotary) body, directly to use a (rotary) body formed massively of after-glowing material. This holds with special advantage in the case of small (rotary) bodies, which are easily producible, at least essentially, as homogeneous (rotary) bodies.
It is preferred to execute the position-sensitive photo-detector by means of a segmented photo-diode. There can be used especially a four-quadrant diode, in which in a preferred form of execution the illumination of the ball occurs through a central opening in the photo-diode. It is then possible to detectxe2x80x94by determination of the relative current or signal strength in the individual quadrantsxe2x80x94how the light spot moves, and therewith does the (rotary) body moves.
Further, it is preferred, with the use of a segmented photo-detector, when the evaluation signals from all the segments can be drawn upon, by which, then preferably a new marking is always set should the light spot of even one of the segments no longer light up. This can be the case especially through the running-out of the light spot from the observation field when using a four-quadrant diode with rapid movement or, especially through the dying-out of the luminescence when using it with slow movement.
It is further preferred to allocate to the light source a pulsed current supply, in which case the current supply is preferably designed always to trigger a light pulse emission when a certain multiple of the afterglow time has elapsed and/or when the light spot is not detected in the desired manner, for example by all four quadrants of a four-quadrant diode, so that the (rotary) body surface is illuminated periodically and/or in response to a relative (rotary) movement and/or speed.
Further it is preferred to send signals relating to the rotation of the rotary body and possibly to the pressing of keys, by radio and/or over an infrared transmission interval for transmission to a computer or the like.